Introducing Zope

Reuven gives a whirlwind tour of the open-source Zope application server, beginning with an exploration of Zope as a web development platform.
Other DTML Methods

There are a number of DTML tags, each of which begins with dtml-. Most DTML tags take one or more parameters, where each parameter allows it to work in a slightly different way. For example, we can modify our test document to include a simple use of <dtml-var expr>:

<p><dtml-var expr="5+10"></p>

The value of our expr in the above code is a simple Python expression. Zope evaluates the expression and replaces the dtml-var tag with the result of that evaluation. We also can try something more interesting than simple addition. For example, we can use the capitalize method in the string module (automatically imported into Zope) by naming it in the expr attribute:

<p><dtml-var expr="_.string.capitalize('abc')"></p>
Notice how we cannot invoke string.capitalize(), but must rather invoke _.string.capitalize().

While DTML allows you to use the string module in this way, you may never have to invoke it directly because so many useful string functions are built into DTML.

DTML was made for designers and other nonprogrammers to be able to create their own dynamic content without being stuck with the poor syntax and documentation of server-side includes. DTML is not as easy for nonprogrammers to learn as some of us might think, but it is far easier than teaching them a full-fledged programming language. And the fact that Zope performs some error checking when saving the DTML document helps to avoid some of the issues associated with runtime languages.

Conclusion

This month, we took a whirlwind tour of several of Zope's features, including through-the-web editing, the management interface, acquisition and simple DTML documents. Next month, we will look at Zope products—how to download and install them, and then how to write our own.

Resources

Reuven M. Lerner owns a small consulting firm specializing in web and internet technologies. He lives with his wife Shira and daughter Atara Margalit in Modi'in, Israel. You can reach him at reuven@lerner.co.il or on the ATF home page, www.lerner.co.il/atf.

______________________

Webinar
One Click, Universal Protection: Implementing Centralized Security Policies on Linux Systems

As Linux continues to play an ever increasing role in corporate data centers and institutions, ensuring the integrity and protection of these systems must be a priority. With 60% of the world's websites and an increasing share of organization's mission-critical workloads running on Linux, failing to stop malware and other advanced threats on Linux can increasingly impact an organization's reputation and bottom line.

Learn More

Sponsored by Bit9

Webinar
Linux Backup and Recovery Webinar

Most companies incorporate backup procedures for critical data, which can be restored quickly if a loss occurs. However, fewer companies are prepared for catastrophic system failures, in which they lose all data, the entire operating system, applications, settings, patches and more, reducing their system(s) to “bare metal.” After all, before data can be restored to a system, there must be a system to restore it to.

In this one hour webinar, learn how to enhance your existing backup strategies for better disaster recovery preparedness using Storix System Backup Administrator (SBAdmin), a highly flexible bare-metal recovery solution for UNIX and Linux systems.

Learn More

Sponsored by Storix